1. Field of the Invention
In medical diagnosis and therapy, surgical operations are being replaced to an increasing extent by the use of endoscopes. This development has been made possible by the development of flexible glass fiber endoscopes. In the course of their intended use, the endoscopes become massively infected with microorganisms which are present in body cavities, on the mucous membrane and in the blood. Accordingly, endoscopes have to be thoroughly cleaned and disinfected after each use.
Glass fiber endoscopes are complex precision instruments which have moving parts and are made from a number of different materials. Because of their construction and diversity of materials, glass fiber endoscopes are extremely difficult to clean and disinfect. The outer surfaces of the instrument and also the narrow bores, present in the interior of the instrument, have to be cleaned and disinfected. In view of the sensitivity of the materials of which the instrument is made, cleaning and disinfection have to be performed in such a way that no residues of the cleaning and disinfecting preparations remain on the treated surfaces of the instrument. The process of thermal sterilization normally used for medical instruments cannot be applied to endoscopes because endoscopes are made partly of temperature sensitive materials. Another factor to be taken into consideration is that many of the metal parts present are susceptible to corrosion. Finally, endoscopes must be cleaned and disinfected in a short time so that they are always ready for the treatment of the next patient.
Only in recent years have manufacturers of glass fiber endoscopes succeeded in developing instruments which may be completely immersed in cleaning and disinfection baths and which are capable of withstanding temperatures of up to 70.degree. C. without damage. Comparable results have been obtained with a number of other medical instruments which are also made of temperature sensitive and/or corrosion sensitive materials.
2. Statement of Related Art
DE-PS 33 27 466 describes a process for cleaning utilitarian medical and patient care articles in which the articles are treated with a standard detergent in a carrier liquid (water) in a closed system at temperatures of at most 70.degree. C. A disinfectant is then additionally introduced into the carrier liquid. The disinfectant used is a mixture of glutaraldehyde and/or succinic acid dialdehyde with a salicylate and a polyethylene glycol. In the practical application of the process, separate temperature holding times are provided for the cleaning treatment and the disinfecting treatment. Alkaline detergent compositions are recommended for the cleaning treatment. This process has proved to be unsuitable for the cleaning and disinfection of endoscopes, because it leads to corrosion phenomena on the metal parts of the endoscopes after only a limited number of process cycles.
The object of the present invention is to develop a process which, through a combination of thermal and chemical treatments, enables heat and corrosion sensitive medical instruments, particularly endoscopes, to be reliably cleaned and disinfected in a short time and which does not damage the treated instruments, even in the event of long-term application. This process is designed in such a way that it may optionally be carried out in an automatic washing machine. In addition, the spent cleaning and disinfecting solutions are sterile so that they may safely be added to the normal wastewater. This object is achieved by the process described hereinafter.